At least five people are dead and more than 160 injured after an explosion at an anhydrous ammonia fertilizer plant in the small Texas town of West. Anhydrous ammonia is a highly toxic, volatile chemical that may have exacerbated the explosion and can blind, suffocate, burn, and kill humans. What is it? And why is it so dangerous?
What is it?
Anhydrous ammonia is a widely used, efficient form of nitrogen fertilizer. When used in agriculture, it's compressed into a clear, colorless liquid and stored at extremely low temperatures. In its natural form, in the open air, it's a gas, so agriculturists use special equipment to compress and handle it, storing it in tanks that can withstand 250 psi. But outside of that tank, it quickly reverts back to its gaseous state. Contact with it as a liquid can cause severe chemical burns and inhaling it can cause damage to the lungs. The "anhydrous" portion of it--"without water"--refers to the fact that the chemical reacts with water, meaning the effects are especially damaging when they combine with the human body's moisture, whether that's in the eyes, lungs, or other parts of the body. When that happens, the reaction forms a highly basic solution that's very corrosive.
Why is it used?
The same thing that makes it dangerous make it useful as a fertilizer. When injected into the soil as a liquid, anhydrous ammonia expands into a gas, where it's more easily absorbed by the soil. Adding nitrogen to soil is a potent way of making the soil more fertile.